Been down a rabbit hole on this lately and honestly the settlement evidence is more scattered than I expected. There are residential sites at Cahuachi but a lot of researchers now think it was more of a ceremonial centre that people visited rather than a permanent town, which sort of fits the "passing through" idea.
What gets me though is the sheer labour involved in maintaining those lines over centuries. That suggests some level of organised, rooted community nearby doesn't it? You dont just pop in from miles away to keep a geoglyph tidy.
My gut feeling is it was probably both - a core group who lived close and maintained the site, and then pilgrims or traders who came through for ceremonies. Similar to how we think about other ritual landscapes.
Anyone here looked into the water source evidence around the pampa? I keep reading that the lines might track underground aquifers and if thats true it changes the whole picture of who was living where and why.